The invention relates to a needling device for mechanically effecting needling procedures according to predetermined parameters and/or measuring the physical and/or electrical characteristics of such needling procedures. The invention also relates to methods of using the invention for mechanically effecting needling procedures according to predetermined parameters and/or measuring the physical and/or electrical characteristics of such needling procedures.
Despite a paucity of rigorous scientific testing, the alternative medicine industry has rapidly grown into a consumer-driven industry, involving annual spending on the order of $14 billion (32). Many alternative therapies are now covered by health plans and taught in medical schools (2a,22a). Consequently, there is a need for research into alternative therapies to validate alternative treatment methods where such validation is warranted, thereby moving valuable treatment methods from the xe2x80x9calternative medicinexe2x80x9d category into mainstream medicine, where they will benefit a larger proportion of society. Additionally, rigorous investigation of the basic mechanisms underlying these treatments will serve to protect the public from fraudulent and ineffective therapies based on false theoretical assumptions.
Proponents of alternative therapies often claim that the beneficial effects of such therapies result from phenomena that are not explainable by the currently accepted scientific paradigm. However, it is clear that many alternative therapies do elicit verifiable therapeutic effects, which are explainable according to modem scientific principles. The failure to elucidate the mechanisms responsible for these effects is primarily due to a lack of rigorous investigation.
Moreover, it is important not to dismiss a priori all alternative therapies on the grounds that they are based on concepts that are not compatible with existing scientific knowledge. Ideas that lay outside of prevailing scientific opinion often spur important advances, and the investigation of alternative therapies can be expected to yield new insights into basic disease processes.
An important aspect of the investigation of alternative therapies is the identification of measurable physiological changes occurring in response to such therapies. Once identified, these physiological changes can be analyzed to determine their relationship to the therapeutic effect. The identification and characterization of such physiological changes is complicated where therapies involve procedures that are difficult to test under double-blind conditions. For example, studies involving alternative therapies are often complicated by placebo responses, which are more pronounced with impressive and exotic treatments (102a).
Acupuncture is a component of a complex therapeutic system that has been used continuously in China for more than 2000 years (15,64,98). Acupuncture has become increasingly popular in the United States and is now performed by thousands of physicians, dentists, acupuncturists and other practitioners. Acupuncture has been investigated more thoroughly than any other alternative therapy; however, much remains unknown regarding the mechanisms that lead to its therapeutic effects (81). In its concluding summary, the 1997 NIH Consensus Development Conference Panel on Acupuncture stated that further research into acupuncture-related biological mechanisms is xe2x80x9cnot only important for elucidating the phenomena associated with acupuncture, but also has the potential for exploring new pathways in human physiology not previously explored in a systematic mannerxe2x80x9d (81).
Acupuncture research has focused primarily on the systemic effects of the use of acupuncture for inducing analgesia. Analgesia can be obtained by prolonged electrical stimulation of acupuncture needles (electroacupuncture). Acupuncture analgesia is reported to involve the repetitive stimulation of sensory afferent nerves and activation of endogenous pain modulation systems (76,102). The local effects of acupuncture needling have, on the other hand, so far received very little study.
A number of factors suggest that local mechanisms specific to acupuncture may play an important role in its therapeutic effect. First, acupuncture involves the needling of acupuncture points, which are traditionally described as discrete points on the body where acupuncture needling produces a maximum effect (94b). Second, correct acupuncture needling elicits a characteristic local response termed xe2x80x9cde qi.xe2x80x9d This response is often described as a sensation experienced by the patient. Importantly however, a biomechanical phenomenon occurs at the site of the acupuncture needling simultaneously with this sensation (18). Finally, it appears that this biomechanical phenomenon occurs maximally when acupuncture points are needled, compared with surrounding tissue (93).
Needle Grasp and Needling Sensation
A potentially important local effect of needling techniques, such as those used to effect acupuncture therapy, is needle grasp. For example, during acupuncture treatments, acupuncture needles are inserted into specific points of the body, known as acupuncture points, and are then manipulated to elicit a characteristic needling reaction termed xe2x80x9cde qixe2x80x9d is observed (1,7,18,20,33,49,53,93). De qi is considered essential to the correct identification of acupuncture points and to the therapeutic effect of acupuncture (18,23,49,66,93,102).
De qi refers to a physiological phenomenon considered essential to guide the correct localization of acupuncture points and appears to be fundamental to the therapeutic effect of acupuncture (18,23,49,60a,66,93,102). In nearly all styles of acupuncture, both manual and electrical, de qi is elicited by insertion and initial brief manual manipulation of the acupuncture needle (1,18,33,49,53,60a,93,99,101). De qi manifests itself in two distinct manners, referred to herein as the two xe2x80x9ccomponents of de qixe2x80x9d: needing sensation and needle grasp.
Needling sensation, the subjective component of de qi, consists of the sensations perceived by the patient during the needling procedure. Typically, patients describe sensations of xe2x80x9csoreness, numbness, heaviness or distention in the area surrounding the needlexe2x80x9d (1,7).
Needle grasp, the objective component of de qi, consists of a change in the mechanical interaction between the needle and surrounding tissue. Needle grasp can be perceived by the patient, but importantly, it also can be directly perceived by the therapist. The therapist perceives de qi as contracting of the tissue around the needle, resulting in increased resistance to further motion of the needle (either axial or rotational). Pulling back on the needle results in a visible upward tenting of the skin and increased resistance to pullout.
Many descriptive terms have been used to convey the acupuncturist""s perception of needle grasp both in ancient texts and in publications representing the entire spectrum of modern acupuncture practice including proponents of both manual and electrical needle manipulation methods: xe2x80x9ctighteningxe2x80x9d (93), xe2x80x9ccontractionxe2x80x9d (23,99), xe2x80x9cgatheringxe2x80x9d (23), xe2x80x9crootingxe2x80x9d (94), xe2x80x9ctensenessxe2x80x9d (7,18,60a), xe2x80x9cheavinessxe2x80x9d (23), xe2x80x9csqueezingxe2x80x9d (49), xe2x80x9cgrabbingxe2x80x9d (49,102), or xe2x80x9cresistancexe2x80x9d (23). Vivid descriptions of needle grasp appear in a review of Japanese Acupuncture (23): xe2x80x9c. . . What at first feels soft, weak and empty at the tip of the needle will gradually tighten up as qi gathers, and it will feel as if the tissue is contracting, with resistance felt at the tip of the needle;xe2x80x9d xe2x80x9c. . . the resistance in the skin increases, the needle seems heavier and there is also a feeling of movement. Conversely, when the needle moves freely back and forth as if it were in a piece of tofu, and there is no feeling of movement, qi has yet to arrive;xe2x80x9d xe2x80x9c. . . a sticky feeling as if stepping into deep mud and being sucked in, or as if one were trying to pick up an upside down umbrella with the handle.xe2x80x9d Occasionally, this mechanical tissue reaction to acupuncture needling can be so powerful that the needle is described as being xe2x80x9c. . . gripped by the skin and often with such force as if held by metal pincersxe2x80x9d (99). Such strong needle grasp reactions are often referred to as xe2x80x9cstuck needle.xe2x80x9d
The mechanisms underlying needle grasp have never been investigated quantitatively, although a variety of opinions have been expressed in the literature. Proposed mechanisms include: contraction of skeletal muscle (20,44,49,96,102), elastic fibers (44), or smooth muscle (57), aggregation of xe2x80x9csubcutaneous fibrous tissuexe2x80x9d (1,7) or perimuscular fascia (58).
Research into the therapeutic effects of acupuncture has been complicated by the heterogeneity of clinical practices now included under the term xe2x80x9cacupuncturexe2x80x9d. Some modern schools use acupuncture principally in the treatment of pain (65). Other schools use acupuncture to treat acute and chronic illnesses, often in conjunction with traditional Chinese herbal medicine (54,62,71). Still other schools use acupuncture to rebalance xe2x80x9cenergeticxe2x80x9d patterns in the body (51,89). The recommendations for acupuncture treatments likewise vary widely: some schools use standardized acupuncture point formulas (2,8) while others emphasize individualized point selection based on a variety of diagnostic and therapeutic systems (23,50,54,71,89,112). Needling techniques also vary in the depth of needle insertion, type of needle stimulation (manual vs. electrical vs. none at all) and duration of stimulation (a few seconds vs. up to 30 minutes).
While most styles of acupuncture involve the insertion of needles at classically defined acupuncture points (1a,6,17,20a,23,33,50,54,72,82a,89,92,99a,101,111), some modem styles disregard acupuncture points in favor of tender or xe2x80x9ctriggerxe2x80x9d points (4,43). However, a study by Melzack (73) found that the location of approximately 70% of commonly found trigger points corresponded within 3 cm to the location of acupuncture points traditionally used for treating pain.
Needle grasp can be used to determine when to remove the acupuncture needles during treatments that employ brief manual stimulation (99). If the needle is left undisturbed once needle grasp has occurred, the tissues gradually relax and the needle can be removed easily, usually after 10 to 20 minutes. With both manual and electroacupuncture, needling sensation and needle grasp both can be used as guides to judge whether or not a needling technique has been performed correctly. When no response is obtained, reintroducing the needle in a slightly different location (often as little as a few millimeters away) frequently results in a strong needling sensation and needle grasp (93). Some schools use only the needling sensation (66), whereas others consider needle grasp more reliable (93).
Investigations of the mechanism underlying de qi reported so far have focused almost exclusively on needling sensation rather than needle grasp. In a study by Chiang et al (19), the needling sensation felt by the patient was prevented by local infiltration of procaine into the xe2x80x9cdeep muscular tissues underlying the acupuncture point,xe2x80x9d reportedly without interfering with the cutaneous sensation, though this last point was not documented quantitatively. In another study by Wang et al (108), recordings were made from microelectrodes placed in the median nerve while manual or electroacupuncture was performed distally. The subjective sensations of xe2x80x9csoreness, numbness, aching, heaviness and distentionxe2x80x9d were respectively correlated with the excitation of different types of afferent nerve fibers. These authors"" conclusions therefore rest on the highly subjective distinction between these various adjectives. Vincent et al (104) carefully established a sensation rating scale using 20 different adjectives to describe the acupuncture needling sensation. When this scale was used in an experiment in which human volunteers were needled at acupuncture and non-acupuncture points, no significant difference was found in the adjectives used by patients to describe the needling sensation at acupuncture points compared with control points.
Empirical observation suggests that needle grasp is a time-dependent phenomenon which begins a few seconds after needle insertion and subsides after 10-20 minutes (99). It is therefore likely to be an active event triggered by the needle and not to be simply passive tissue resistance. Moreover, the tissue relaxation occurring after needle grasp can be used to determine the timing of needle removal and is potentially an important factor in the therapeutic effect of acupuncture.
Acupuncture Needling Techniques
Although needle grasp can be observed with simple needle insertion (without further needle stimulation), the amount of tissue reaction appears to be related to the type and amount of needle stimulation.
Brief manual stimulation of acupuncture needles for a few seconds is used in nearly all types of acupuncture (manual and electrical) for the initial identification of each acupuncture point (1,18,33,49,53,93,101). The acupuncturist inserts the acupuncture needle, then applies rapid up and down or rotatory motions to the needle, while observing for signs of de qi. Some acupuncturists principally rely on the needling sensation(66), which requires feedback from the patient. Other acupuncturists consider needle grasp more reliable (93) as a sign of de qi, since it can be observed directly. Many acupuncturists use both.
Once de qi has been elicited, supplementary stimulation may or may not be applied to the needles depending on the style of acupuncture, the type of treatment, and the clinical situation. Acupuncture analgesia (especially for surgical procedures) requires prolonged manual or electrical stimulation of needles, often for up to 30 minutes (2). Some schools of acupuncture remove needles as soon as de qi is observed; others leave needles in place without further stimulation and remove them after a period of time; still others use intermittent manual stimulation to reelicit de qi over the course of 15 to 30 minutes (93,99).
Electroacupuncture is achieved by connecting the needle to an electrostimulation device delivering pulses at frequencies generally ranging from 2 to 200 Hz(101).
The two fundamental manual needle manipulation techniques are: 1) lifting and thrusting (i.e., the needle is moved back and forth along its path of insertion); and 2) twisting and rotating at a constant needle depth. Rotation of the needle can be either unidirectional (rotating in one direction only) or bidirectional (rapid back and forth rotation). Unidirectional rotation can elicit strong needle grasp reactions (often referred to as xe2x80x9cstuck needlexe2x80x9d) that can become painful with excessive prolonged manual or electrical stimulation. Unidirectional rotation is therefore not the method of choice for eliciting de qi in acupuncture analgesia. However, both unidirectional and bidirectional rotation are used in other types of acupuncture treatment (49,53,94,99). When needle stimulation is brief (a few seconds), neither unidirectional nor bidirectional rotation cause significant pain, even when strong needle grasp is elicited. A large number of subtle variations on the basic needle manipulation techniques are described in acupuncture textbooks, along with indications for different pathological conditions (1,7,18,33,53).
Location of Acupuncture Points
There has been an ongoing debate among acupuncturists as to the specificity of the acupuncture points described in the classical Chinese literature (102,103). The traditional theory of acupuncture is based on the premise that there are patterns of energy flow through the body that are essential for health (81). The network of acupuncture points and meridians is the traditional anatomical framework upon which these patterns are drawn. Some acupuncture points are linked together by meridians, while others are xe2x80x9cextraxe2x80x9d points outside the meridian system. Moreover, some modern acupuncturists use techniques which disregard traditional acupuncture points (4,43).
The traditional Chinese method of locating acupuncture points on the surface of the skin uses references to both anatomical landmarks (such as bony prominences or skin creases) and proportional measurements (based on the width and length of various portions of the body) (16). Within the area delineated by these landmarks, the precise location of the acupuncture point is traditionally determined by gentle palpation. The acupuncturist feels for a slight depression or yielding of the tissues, which the patient often reports as locally tender (23,49,99a,101).
There is a need in the art for a means for quantifying needle grasp, e.g., by measuring the force required to insert a needle into tissue, the force required to pull a needle out tissue or by measuring torque as the needle is rotated. There is a need in the art for a mechanical device, preferably controlled by a computer, that can make accurate and reproducible outcome measurements (e.g., measurements of physical and/or electrical characteristics) relating to needle insertion, manipulation and pullout to enable study of needling techniques in a manner which will eliminate potential sources of investigator bias.
There is a need in the art for a diagnostic instrument for diagnosing conditions associated with tissue pathologies that can be detected by needling techniques using the instrument.
There is a need in the art for a tool that can mechanically insert and manipulate a needle (such as an acupuncture needle), measure the pullout force, measure depth of needle insertion, measure needle rotation torque, and record electromyographic evidence of muscle penetration.
There is a need for a miniaturized needling instrument which is light-weight and easy to operate, which can mimic manual acupuncture technique in a precisely reproducible manner.
There is a need in the art for a means for objectively and quantitatively differentiating acupuncture points from non-acupuncture points.
There is a need in the art for a mechanical needling instrument which can elicit de qi.
The invention relates generally to a needling device and to therapeutic, diagnostic, and research methods for using the device.
In one aspect, the invention provides a hand-held needling device for measuring pullout force required to remove a needle from tissue of a subject and/or torque resulting from rotation of a needle in a subject. The device generally comprises a shaft, a needle grip mounted at an end of the shaft, a needle suitable for in vivo use in an animal or a human mounted in the needle grip, and one or more of the following components: (i) a mechanism for providing an output indicative of pullout force coupled to the shaft or the needle grip; and (ii) a mechanism for providing an output indicative of torque caused by rotation of the needle coupled to the shaft or the needle grip.
As an example, the mechanism for measuring pullout force may suitably comprise a spring scale mechanism. The spring scale mechanism may, for example, comprise a spring comprising a first arm extending tangentially from a first end of the spring and a second arm extending tangentially from a second end of the spring, wherein the first and second arms are biased towards one another, the first arm is coupled to a tubular handle through which the shaft is inserted, and the second arm is coupled to the shaft. Alternatively, the spring scale mechanism may comprise a spring joined at an end to a tubular handle wherein an end of the shaft opposite the attachment of the needle mount is inserted first through the spring and then through the tubular handle, and wherein an end of the spring opposite the end joined to the tubular handle is joined to the shaft.
The needling device suitably comprises a mechanism for providing an output indicative of pullout force coupled to the shaft or the needle grip and/or a mechanism for providing an output indicative of torque caused by rotation of the needle coupled to the shaft or the needle grip. Either of these mechanisms may, for example, be a loadcell, and both mechanisms may be provided in a single loadcell.
In a more complex aspect, the invention provides a needling apparatus generally comprising a elongated encasement, a needle mount slidingly mounted within the elongated encasement and adapted to receive and hold a needle, and one or both of the following actuators: (i) a linear actuator mounted within the encasement and adapted to impart linear motion to the needle mount longitudinally, and (ii) a rotary actuator mounted within the encasement and adapted to impart rotational motion to the needle. These actuators may, for example, comprise motors.
In any of the aspects of the invention, the needle mount suitably comprises a quick-release device, such as a collet clamp. The needle mount may, in certain aspects of the invention, be adapted to receive and hold the blunt end of an acupuncture needle. The needle mount is also suitably adapted to establish electrical continuity with the needle such that EMG signals may be detected using the acupuncture needle as an EMG probe. A switch may be provided to establish and break the electrical continuity. An EMG amplifier may be provided to amplify EMG signals for transmission to an analog power meter.
In one aspect, the needling device comprises contacting extension or xe2x80x9cfootxe2x80x9d at an end of the encasement for resting against a subject to stabilize the device during needle insertion. This extension may suitably comprise a loadsensor for detecting and generating an output indicative of the amount of force with which the needling instrument of the invention is being held against the subject.
In another aspect of the invention, the needling device comprises an activation switch for activating the linear actuator to cause the needle mount to extend axially thereby extending the needle out of an end of the device for insertion into a subject and/or an activation switch for activating the rotary actuator to cause the needle mount to rotate after insertion into a subject. In a related aspect, a single activation switch may be configured such that: (a) when pressed a first time, the linear actuator is activated thereby causing the needle mount to extend longitudinally out of an end of the device for insertion into a subject; and (b) when pressed a second time: (i) the rotary actuator is activated, thereby causing the needle mount to rotate after insertion into a subject; and (ii) the linear actuator is subsequently activated, thereby causing the needle mount to retract longitudinally after completion of rotation. In another related embodiment, the needling device may comprise one or more activation switches configured to provide power to the linear and rotary actuators to sequentially provide the following functions: (a) activation of the linear actuator to cause the needle mount to extend longitudinally forcing the needle out of an end of the device and into a subject; and (b) activation of the rotary actuator to cause the needle mount to unidirectionally or bidirectionally rotate after insertion into a subject; and (c) activation of the linear actuator to cause the needle mount to retract thereby removing the needle from the subject.
In another aspect, the linear actuator comprises a miniature DC servomotor. The motor may, for example, be coupled to the needle mount by a lead screw device. In another aspect, the rotary actuator is a miniature DC servomotor. Either or both the linear and rotary actuators may be configured as a stepper motor, such that its speeds, direction, and distance of travel can be controlled by a computer using an open-loop control system.
In yet another aspect of the invention, the needling instrument comprises a linear variable displacement transducer mounted in the elongated encasement for providing a measure of axial needle position. A uniaxial strain gauge loadcell may also be provided to measure the axial load applied to the needle during both needle insertion and/or needle pullout.
The needling device of the invention may also employ a computerized control system adapted to control the linear and rotary actuators in a manner which permits insertion, manipulation and retraction of a needle held by the needle mount. The computerized control system may, for example, be suitably configured to control insertion, manipulation, and retraction of the needle by one or more activation switches mounted to the needling device.
An activation switch may also be provided to generate a signal instructing the computerized control system to zero the loadcell in its starting position and to begin sampling data.
The computer control system may also be suitably programmed to continuously monitor parameters of needle insertion and to terminate operation of the needling device if one or more parameters exceeds a predetermined threshold. As an example, preferred thresholds include (a) needle being inserted more than about 2 mm deeper than a target depth, and/or (b) a maximum insertion or pullout force reaching 3.9 N.
In a safety aspect of the invention, the needling device may be configured such that the axial travel of the needle grip is limited by mechanical stop. The mechanical stop is conveniently provided by contact of the needle mount with the contacting extension. Moreover, all or substantially all of the electrical components may be powered by one or more low voltage batteries. Electrical connections between the needling device and the control and data acquisition system may suitably incorporate optical isolation amplifiers.
In a method aspect, the needling device is used to effect one or more of the following steps: (i) insert a needle into an acupuncture point of a subject; (ii) manipulate the needle; and (iii) withdraw the needle. These steps may be performed as components of a therapeutic needling regimen. The therapeutic needling preferably elicits needle grasp, and more preferably elicits de qi.
In a related method aspect, the invention relates to a method for diagnosing an adverse medical condition by using the needling instrument to (i) insert a needle into a subject; (ii) manipulate the needle; (iii) withdraw the needle; and (iv) measure physical and/or electrical parameters associated with (b), (ii), and (iii). These steps are not necessarily sequential, since the measuring step may be ongoing throughout the insertion, manipulation and withdrawal steps. The physical and/or electrical parameters may be compared with normal physical and/or electrical parameters; the presence of abnormal physical and/or electrical parameters is indicative of the presence of an adverse medical condition.
In a related aspect, the invention provides a method for obtaining physical and/or electrical data elicited by needling techniques by using the needling device to do one or more of the following: (i) insert a needle into a subject; (ii) manipulate the needle; (iii) withdraw the needle; and (iv) measure physical and/or electrical parameters associated with 44(b), 44(b)(ii), and 44(b)(iii). Here again, the steps are not necessarily sequential, since the measuring step may be ongoing throughout the insertion, manipulation and withdrawal steps.